The nucleic acid is used in various fields in various forms. For example, in the field of recombinant nucleic acid technology, the nucleic acid is required to be used in the form of a probe, a genomic nucleic acid, and a plasmid nucleic acid.
In diagnostic field, the nucleic acid is also used in various methods, For example, a nucleic acid probe is normally used in detection and diagnosis of a human pathogen. Similarly, the nucleic acid is used in detection of genetic disorders. The nucleic acid is also used in detection of a food contamination substance. In addition, the nucleic acid is normally used in positioning, identification and isolation of an interesting nucleic acid by various reasons such as preparation of a gene map, cloning and expression of recombinant.
In many cases, the nucleic acid can be obtained in a very small amount, and a complicated and time-consuming operation is required for isolation and purification. This frequently time-consuming and complicated operation is easy to cause a loss of the nucleic acid. In purification of the nucleic acid obtained from serum, urine and bacterial culture, risks such as occurrence of contamination and pseudopositive result are added.
One of well known purification methods is exemplified by purification by adsorption of the nucleic acid to the surface of silicon dioxide, silica polymer or magnesium silicate followed by operations such as washing and desorbing (Japanese Examined Patent Application Publication No. 1995-51065.) This method is excellent in separation performance, however, there are problems that (1) it is difficult to industrially produce the adsorption medium of a comparable performance in a large scale, (2) the handling of the medium is inconvenient, and (3) it is difficult to process the medium in various shapes.